Ionic, Covalent and Metallic Bonding

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  • Created by: Rumana.A
  • Created on: 13-04-18 08:40
What is Ionic bonding?
Electrostatic attractions between positive and negtaive ions
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Why do Ionic compounds have giant structures?
Ions are arranged in a regular; three- dimensional pattern called a lattice, forces between the ions act in all directions which keeps the structure together. Large number of these attractions gives high melting points
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What are positive ions?
Formed by metal atoms losing electrons, have a positive charge = to group number,have different charges if formed from a transition metal, AKA cations
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What are negative ions?
Formed by non- metal atoms gaining electrons from metal ions, have a negative charge = to 8 minus group number, AKA anions
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What happens when an atom loses electrons?
Becomes positively charged
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What happens when an atom gains electrons?
Becomes negatively charged because of the imbalance of protons and electrons
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What is Covalent bonding?
Electrostatic attraction between a shared pair of electrons
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How do atoms form covalent bonds?
Forms when atoms share a pair of electrons- each atom contributes one electron to the pair
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What is dative covalent (coordinate)?
Covalent bond consisting of an electron pair derived from one of the atoms
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How is covalent bonding shown?
Dot & cross diagrams- dots = electrons from one atom, cross= electrons from the other atom, circles= shells (only outer electrons need to be shown)
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What is the lone pair?
Pair of non-bonded atoms
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What is the strength of covalent bonds?
Length and strength in covalent bonds are inversely related= the shorter the covalent bond length, the greater the covalent bond strength
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What is an organic compound?
A compound that contains one or more carbons in a carbon chain
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What is Metallic bonding?
Type of metallic bonding that arises from the electrostatic attractive force between conduction electrons and positively charged ions
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What causes metallic bonding?
Electrons in the highest energy level of a metal atom has the ability to become delocalised
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What are 'delocalised electrons?'
They are electrons from the outer shell of the metal atoms but not fixed to a particular atom, so can move freely throughout the structure
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What are some of the properties of metals?
Thermal conductivity, high melting and boiling points, malleability and ductility
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What is thermal conductivity?
Its happens due to the delocalised electrons, which are free to move
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What are the high melting and boiling points for?
Due to strong electrostatic attractions between positive ions and electrons
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What does malleability mean?
Can be shaped, as layers of positive ions slide over each other and the delocalised electrons move with the layers, so strong metallic bonds remain intact
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What does ductility mean?
Can be pulled into wires as positive ions roll over each other and the delocalised electrons move with the positive ions, so strong metallic bonds remian intact
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What happens when the melting point decreases?
Atoms becomes larger, larger metals have more electron shells- means more sheilding between the nucleus and delocalised electrons so electrostatic force is weakened. This produces a weaker metallic bond so less energy is needed
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What happens when the melting point increases?
Group 2 metals have a higher melting point than Group 1 metals even though they're in the same period. BECAUSE group 2 metal has two delocalised electrons rather than one= greater electron density, +2 charge, produces stronger attraction
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What are non-polar molecules?
Electrons are distributed evenly throughout the molecule e.g covalent bonding in chlorine
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What are polar molecules?
A molecule with partial positive charge in one part of the molecule- uneven electron distribution
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Other cards in this set

Card 2

Front

Why do Ionic compounds have giant structures?

Back

Ions are arranged in a regular; three- dimensional pattern called a lattice, forces between the ions act in all directions which keeps the structure together. Large number of these attractions gives high melting points

Card 3

Front

What are positive ions?

Back

Preview of the front of card 3

Card 4

Front

What are negative ions?

Back

Preview of the front of card 4

Card 5

Front

What happens when an atom loses electrons?

Back

Preview of the front of card 5
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